This is a follow-up tidbit on the subject of Alum. See my first article here and my second article here.

For a couple months now I've been talking about the crystal deodorants and how they still do contain aluminum even though most of them claim to be "aluminum-free." I wrote about how crystal deodorants are made up of potassium alum, the nickname for potassium aluminum sulfate. Once the potassium alum is wetted, as one would do using a crystal deodorant, it dissolves into ionic aluminum. Ionic aluminum is the smallest form of aluminum possible. My argument is that if larger molecules such as aluminum chlorohydrate pose a health risk by absorption, aluminum ions would as well. Although I found a number of empirical studies that would suggest ionic aluminum is absorbed through the skin, I had yet to find a direct study stating that aluminum ions are absorbed through the skin. Today I am glad to say, I found the research.

A French study published in the Journal of Biomedical Materials Research explored the effects of aluminum ions on collagen. As stated in the study's introduction, "Heavy metal ions are capable of inducing crosslinking between peptide chains of collagen. The metal ions improve the capacity of collagen to resist denaturization as well as the attack by enzymes, bacteria, and chemical agents." [p 1339] In other words, metal ions have been found to stabilize collagen. This is a process that is used in the leather-making industry (known as "tanning" hides) and in some medical devices/products.

Chromium salts were already well-known to be a good collagen stabilizing agent at the time of the study. The purpose of the study was to find if aluminum ions, as found in aluminum salts, had the same collagen stabilizing effects, and could be used in the same way industrially to tan hides and to create collagen-based medical materials.

The researchers treated collagen with aluminum ions and found that it became significantly dehydrated. They concluded that "the substitution of water molecules by aluminum ions on intramolecular hydrophilic sites is suggested to be responsible for this evolution." In other words, the aluminum ions substituted the water molecules in the collagen, thus drying it out. This may explain why alum has a drying effect on skin-- as it robs the collagen of its moisture, aluminum ions replacing water molecules.

The researchers studied the effects of aluminum ions on both extracted collagen and skin tissue. The aluminum ions were found to affect the collagen in the skin samples. Thus, we can ascertain that the aluminum ions were absorbed into the skin at some level. The deodorant companies' claims that their aluminum molecules are "too large to be absorbed through the skin" are thus disproven.

Aluminum ions, as found in crystal deodorants, are absorbed through skin, and do have a biological reaction therein.

I use the pit putty, but my husband still smelled pretty rank after weeks of regular deodorant detox, so he switched to plain old baking soda, and he swears by it. It makes a gritty mess in the bathroom, but I already tolerate his whiskers, so I guess it's a wash!

I've got to question how you can generalize a study about aluminum ions to include an aluminum compound, which is found in crystal deodorants. These mineral deodorants claim that the compound is too big to be absorbed, and I don't see anything in this study that refers to aluminum compounds specifically, just aluminum ions themselves.

That's because the form of aluminum in the crystal IS ionic aluminum. When you have a salt (such as potassium aluminum sulfate) and you dissolve it in water (such as what you do when you wet the crystal) that salt disperses as ions in the water. So, when you apply the crystal salt solution to your skin, you're applying ionic aluminum. Their assertion that the crystal is too large to be absorbed is false.

Does anyone else find that, after using salt crystal deodorant for a long time, starts to suffer from dry itchy skin on their body? Also found that my clothes have become ruined too. After washing them as they look & feel like they've been washed in salt water. Some of my clothes get 'salt water' white patches on them. I get a terribly itchy from my clothes ( and yes I've eliminated ask the obvious allergens like detergents etc)

So the claim is that aluminum does get absorbed into your skin. I agree with the aluminum ions being absorbed into the skin, but considering the amount and solubility of the aluminum salt, what would be the concentration of these ions that actually dissolve and get absorbed? Did the study state that? Or is the study simply making a claim that it interferes with collagen when absorbed but does not give any information regarding the affect on levels in the bloodstream. Which is what most people are afraid about due to health concerns. If two in every 1000 aluminum molecules gets absorbed, then the amount is almost negligible. Just curious if there was more information.